It is to the body alone that we should attribute everything that can be observed in us to oppose our reason.

Everything is self-evident.

What then is the source of my errors? They are owing simply to the fact that, since the will extends further than the intellect, I do not contain the will within the same boundaries; rather, I also extend it to things I do not understand. Because the will is indifferent in regard to such matters, it easily turns away from the true and the good; and in this way I am deceived and I sin.

It is not enough to have a good mind. The main thing is to use it well.

The rainbow is such a remarkable phenomenon of nature, and its cause has been so meticulously sought after by inquiring minds throughout the ages, that I could not choose a more appropriate subject for demonstrating how, with the method I am using, we can arrive at knowledge not possessed at all by those whose writings are available to us.

God alone is the author of all the motions in the world.

There is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.